[Using OCAD 6] Basically, the open woods symbol is not a symbol at all, it is absence of any symbol. Was there ever a need for one ? while converting vegetation features from one symbol to another while creating a map that was different from the Orienteering map standard, felt the need for the existence of a symbol for "open woods" (white). Maybe in later versions of OCAD ?
Its very useful for putting white areas inside of a green area. Easier to deal with than cutting a hole in many cases.
Scattered tree cover in large clearings is easier with white over yellow symbol. Yellow over green can be a useful symbol as well.
Basically, yeah, it's the lack of a symbol, but in the standard symbol set in some versions, there's a "white for green" and a "white for yellow". I don't remember whether that was the case in 0CAD 6. (I think it was a standard symbol. Or did I create it for my custom set?) In any case, you could create one.
I was making several CRT conversion tables recently, going through several symbols sets one-by-one, and I noticed that the standard symbols for OCAD skip symbol 405, which is "Forest: Easy Running". It might make sense to use a 405.1, 405.2, etc, numbering scheme for "white over x" symbols. I don't think I've seen that done before, but I don't see the personal symbol sets of very many serious mappers.
You should distinguish "OCAD" from "symbol set". You can use a set that comes with OCAD, you can make your own, or more commonly modify an OCAD-provided one. The OCAD-provided ones, and associated colours, have changed over the years.
But back to the issue. I prefer to cut holes rather than achieve effects by relying on one colour being "over" another colour. But I do draw patches of 405 for a particular reason. I have mapping that is used for MTBO and rogaining. I may want passable forest to be white (MTBO) or light green (more intuitive for rogainers). I can quickly edit symbol 405 to achieve this. I have other multi-purpose mapping that can be changed by editing a few symbols.
I prefer cutting/flling holes to keep the drawing as clean as possible, making it much easier for someone doing revisions later. I do occasionally turn to a 405 which I have in "my" OCAD symbol set but when I do, I temporarily shade it light 10-20% purple so I can see where it's used while drawing.
Over the years my personal symbol set has become pretty extensive containing a large number of "helper" symbols most of which are deleted once the map is completed. Non ISOM examples include basemap symbols, temporary draft symbols for tracing field scans, or point symbols corresponding to minimum sizes for yellow areas I can use for comparison.
I also have a few secondary ISOM symbols used, for example, drawing short trails or rides (no dashes) or short fences (no tags).
I definitely prefer cutting / filling. I recently had to edit a map where the mapper did both cutting and overlaying in some large rough open field areas (where parts have been mowed, other parts have grown up with white or green.) Additionally, the mapper merged several adjacent fields into one big convoluted patch of rough open, and the editing was almost impossible - some places I just had to go in and redraw because I could not figure out any way to make the cuts that were needed..
OK, I thought about it some more, and what I'm remembering (shows how rusty my 0CAD skillz are getting) is that there are/were colors called WhiteForGreen and WhiteForYellow. The latter, for example, is used to make the dots in rough open with scattered trees. Since those colors exist, I went ahead and created symbols using them in my customized symbol set, but I rarely if ever use them, preferring in general to cut holes. You have to be careful with holes, though. You can cut a hole that's outside the object, or inside another hole and those appear as anti-holes, and if two holes overlap, they cancel each other out (XOR for you nerds). I've worked on maps drafted by others who lost track of whether they were drawing or cutting, and created a mess. Two overlapping patches of white, in contrast, are still white.
Who are you calling a nerd? :p
To speak up for white over yellow. I used white over yellow on a sprint map to represent tree canopy in a generally open area. Most of the canopy areas were single trees. The land owner embarked on a selective tree felling program to reduce public risk. I just had to delete a number of white objects. Don't see how editing can get much simpler than this. I find the editing of holes to be tedious.
You can also delete holes, you realize. But that's an excellent example of where the white is the "thing" (the figure, as opposed to the ground), and thus it makes sense for it to be the symbol, rather than the hole.
I recently converted an urban foot map to MTBO and the previous mapper had used 'white' rather than holes but unfortunately the white tended to cover up a lot of the stuff that I needed to be as not white (I forget specific details but it may have been tracks or some such) so I had to delete the white and redo it as holes.
Manipulating the colour table order may have been easier.
No it wouldn't. I wanted to use 'white on green' or whatever for road and track framing*. Not helpful when it just hides the whole thing.
*I forget the real reason but it was complicated.
This discussion thread is closed.